Underwater bay grasses covered 79,675 acres of the Chesapeake Bay and its tidal rivers in 2010, according to data from scientists with the Chesapeake Bay Program. This is a 7 percent decrease from 2009, when bay grasses covered 85,914 acres of the Bay’s shallows.

Despite the drop, the 2010 bay grass acreage estimate ranks as the third-highest Bay-wide acreage since 1984, when the annual survey began.

"Even with the decreases in the 2010 bay grass coverage, the patterns are similar to previous years,” said Lee Karrh, living resources assessment chief with the Maryland Department of Natural Resources and chair of the Bay Program's SAV Workgroup. “Many of the fresh and low salinity areas have very high abundances, including 16 that have reached their restoration targets. However, the saltier parts of the Bay continue to struggle, with most areas well below the restoration goals, with only the mouth of the James River exceeding the goal.”

The Bay continues to struggle to keep or even increase its SAV. SAV is an important habitat for fish and invertebrates. We don't know all the answers, but we think that eutrophication is a large part of the problem; excess nutrients cause phtyoplankton or epiphytic algae to bloom and starve the SAV of light. Within living memory (but not mine) the bay had much higher coverage of SAV than it does now. Many people trace the turning point in the loss of SAV to Hurricane Agnes in 1972, which flooded the Bay watershed with rain and lowered the salinity well below normal level, brought huge amounts of suspended sediments into the bay, and choked many areas with silt. On the other hand, it could just be eutrophication, and Agnes just occurred in the middle of its growth, and Agnes is unfairly blamed for the results.